Background. The badminton forehand overhead jump smash is one of the high speed and powerful motions among various racket sports. Objectives. The purpose of this study is to analyze the effect of fatigue on the kinematic variable movement changes during overhead jump smash in badminton. Methods. This study is descriptive quantitative research with the pre-test and post-test design methods used to obtain data from 15 male badminton players, aged 19.4±1.6 years, height 1.73 ± 0.12 m, and weight 60.8 ± 3.7 kg. The study used three high-resolution handy-cams, motion software Frame DIAZ IV, and 14 point manual markers to analyze body segments' movement when carrying out a jump smash. Furthermore, an ergo treadmill was used to test the players' level by running. Results. The results showed that the shuttlecock velocity was faster during pre-fatigue (188 km/h) than under the condition (145 km/h). A significant difference showed in the angle of shoulder internal rotation (p=0.048) and wrist palmar flexion (p=0.037) at the instant of maximal shoulder external rotation phase. Furthermore, there were significant differences in the shoulder's internal angular velocity (p=0.042), elbow extension (p=0.035), forearm supination (p=0.024), and wrist Dorsi dorsiflexion.040). Conclusion. In conclusion, fatigue reduces players' performances during jumping smash in badminton, thereby leading to slower shuttlecock speed and changes in body segment movements.

The purpose of this study was to analyze the joint motion kinetics of the shoulders, elbows, and wrists between experienced player (skilled player) group and unskilled player group when performing overhead standing smash in badminton game. The samples involved were 26 samples. The samples included 13 male badminton players joining Student Activity Unit who had achieved many achievements and had a high skill (skilled), while the other 13 samples were unskilled players, involving students who had just studied under one year. The mean of participants’ age was 19.4 ± 1.6 years, height was 1.73 ± 0.12m, and body weight was 62.8 ± 3.7kg. This study used 3 Panasonic Handycams, a calibration set, 3D Frame DIAZ IV motion analysis software, and a speed radar gun. Normalization of the kinetic motion score of the shoulder, elbow, and wrist joints was calculated using the inverse dynamics method. The t-test was used to determine the significance of motion kinetic difference of the two different groups. The results presented that the shuttlecock speed of the skilled player group, during the overhead standing smash, showed a significant difference. Meanwhile, the joint motion of the inferior shoulder force, shoulder anterior force, shoulder internal rotation torque, shoulder horizontal abduction torque, elbow anterior force, and wrist flexion torque were higher in the skilled players group than the unskilled player group.

This study aims to develop a Maximal aerobic capacity measuring device through a digital-based bleep test using infrared sensors and software motion analysis systems in order to obtain more accurate assessment results and work efficiency in conducting tests. The research method used by researchers is the R & D method (research and development), in collaboration with a team of experts in various specific fields so that in the development of this research, researchers can create a product that can be validated before being mass produced. The results of this study will create a digital-based measuring instrument that has been tested for validity with the results stated VALID. With the existence of research that develops a product can avoid errors, or Human errors in the execution of tests, get accurate results compared to testing manually and work more efficiently.Keywords: Maximal aerobic capacity, Bleep test, Infrared Sensor and Motion Analysis system software AbstrakPenelitian ini bertujuan untuk mengembangkan alat ukur Maximal aerobic capacity melalui  bleep test berbasis digital dengan menggunakan sensor infrared dan software motion analysis system supaya mendapatkan hasil penilaian yang lebih tepat, akurat dan efesiensi pengerjaan dalam melakukan tes. Metode penelitian yang digunakan oleh peneliti adalah metode R&D (research and Development), bekerjasama dengan tim pakar atau ahli dalam berbagai bidang tertentu supaya dalam pengembangan prototype sederhana ini yang dapat menciptakan suatu produk yang dapat divalidasi sebelum diproduksi secara massal. Hasil dari penelitian ini akan menciptakan suatu alat ukur berbasis digital yang sudah dilakukan uji validitasnya dengan hasil dinyatakan VALID. Dengan adanya penelitian yang mengembangkan suatu produk dapat menghindari kesalahan atau Human error dalam pengerjaan tes ,mendapatkan hasil yang akurat di bandingkan tes secara manual dan pengerjaan lebih efesien.

Background: Overhand pitching is a movement that requires the coordination of lower extremity, trunk, and upper extremity segments to effectively transfer force throughout the kinetic chain to project a baseball. Objective: The purpose of this study was to investigate the effect of cardiorespiratory fatigue on throwing ball velocity related to kinematics motion changes in baseball. Methods: The study samples included 12 male baseball athletes (19.3 ± 2.8 years old, height of 1.71.4 ± 3.1 m, and weight of 64.3 ± 3.6 kg). A descriptive quantitative method approach was used. The instruments included two high-resolution handycams (Sony HXR-MC2500, Japan), a high-speed camera (Fastec Imaging TS5-H, USA), a radar speed gun (Bushnell 101922, Germany), a 3D force platform (The AMTI Optima Series 20210, USA), 14 point manual markers, a motion capture system software (Frame DIAZ IV, Japan), and a heart rate sensor (Polar H10, Finland). Results: The results of this study showed that there were significant differences in the ball velocity (p= 0.042), stride length percentage height (p= 0.041), elbow flexion (p= 0.046), maximum shoulder horizontal adduction (p= 0.041), maximum elbow extension angular velocity (p= 0.035), maximum shoulder internal rotation (p= 0.029), and lateral trunk tilt (p= 0.029) when the pitchers were fatigued. Conclusion: Cardiorespiratory fatigue causes changes in the kinetic harmonization of upper and lower body motion, which results in a decrease in the ball velocity. These results are similar to those in previous studies conducted with the intervention of muscle fatigue during overhead baseball throwing, which causes a decrease in the performance and ball velocity.

The submerge, float, and glide ability are first or basic factor that can determine a person is able to swim naturally and can also be easier when learning swimming skills. The aim of study was to investigated contribution of submerge, floating, glade as basic swimming ability on swimming distance ability. Forty student colleges sport science (n=26) and Mathematical (n=14), age range 19 to 21 years (female 17), and (male 23). Subject category of beginner swimmers. They are semester III, and are enrolled in 2017. The applied test have been constructed in order to submerge, floating, gliding ability, as predictor and swimming distance ability as achievement reference standard. The study uses descriptive predictive method. Data collection Instruments use direct test in water. Descriptive statistics analysis (mean, St. d, minimal, maximal, and range). Inferential analysis of prediction using Person partial correlation and multiple linier regressions for predictive validity. Results; coefficient correlation submerge with floating r = 0.60 (sig. p > 0.00), moderate category. Submerge with gliding r = 0.34 (sig. p > 0.034), low category. Submerge with swimming distance (reference standard) r = 0.53, r2= 0.28 (28 %) (sig. p > 0.00), moderate. Floating with gliding r = 0.33 (sig. p > 0.04), low category. Floating with swimming distance r = 0.32, r2= 0.10 (10 %) (sig. p > 0.04), low category. Gliding with swimming distance = 0.38, r2= 0.14 (14%) (sig. p > 0.02), low category. All three factor variables have a positive relationship internal factor, but it is in the moderate and low category. The three components of the basic swimming ability as a predictor has a contribution to the ability of swimming distance of beginner level students with a value coefficient determination of 33 %. The remaining 0.67 % resulted from the other ability. Physical education or beginner swimming trainers should teach these basic skills first before learning swimming techniques.